The present invention relates to a tooth brush comprising a brush handle, a brush stem, and a brush head which carries on the base face thereof a plurality of bristle tufts rising up in a generally uniform direction.
Tooth brushes of the above kind are known conventionally and in widespread use in designs for both manual operation and electrical operation.
A drawback of all conventional tooth brushes is the insufficient cleaning efficiency in the area of the gaps between teeth. This is due to the fact that normally a rigid brush head carries a bristle array including a plurality of bristle tufts which define a substantially planar and coherent bristle surface. However, as the teeth do not define a planar surface, complete or at least sufficient cleaning of the gaps between teeth is not, or hardly, possible. The bristles of such brushes may enter the gap between teeth only with a correspondingly large deformation of the adjacent bristles. To this end, a correspondingly high pressing force must be exerted on the brush head; however, this may result in damage to the hard substance of the teeth, e. g. in wedge-shaped cleaning defects on the necks of teeth, in the course of time. Further, so high a pressing force results in the feeling of pains in the gums (gingiva), whereby a user of a tooth brush is caused to exert a lower pressing force. Finally, it is a further drawback that the bristles in a short time become deformed permanently under a high pressing force against the surface of the teeth thereby further impairing the cleaning efficiency. Actually, an adequate cleaning effect may be obtained even with the above-described tooth brushes when specific teeth cleaning techniques are adopted; in practice, however, it can be observed that such techniques are too complicated, such that these techniques are rarely practised.
Furthermore, attempts have been made to improve the cleaning efficiency by adopting special positions or attitudes of individual bristle tufts or groups of tufts, e. g. V-position or inclined position; in practice, however, any deciding improvements could not be obtained thereby, because the fundamental drawbacks of conventional tooth brushes exist as before.